一.流程
1.获取CameraManager
2.通过CameraManager根据ID获取摄像头参数CameraCharacteristics,获取输出尺寸
3.通过CameraManager开启摄像头，并在回调中获取到CameraDevice对象。
4.通过CameraDevice对象创建CameraCaptureSession。
5.构建CaptureRequest请求,分别有预览/拍照/录像三种模式
6.通过CameraCaptureSession发起请求（capture方法只发一次, setRepeatingRequest方法会一直发）。
7.在ImageReader的回调中处理拍照结果。
二.各个流程代码
1.获取CameraManager并获取摄像头参数
2.用CameraManager开启摄像头，并在回调中构建预览请求，通过session发送请求
3.创建ImageReader的回调
4.构建拍照请求，并用session发起请求，拍照的数据在ImageReader的回调中处理，自己定义方法就行了
三.完整代码
activity代码：
package com.example.administrator.servicereceiver;
import android.Manifest;
import android.content.Context;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.ImageFormat;
import android.graphics.SurfaceTexture;
import android.hardware.camera2.CameraAccessException;
import android.hardware.camera2.CameraCaptureSession;
import android.hardware.camera2.CameraCharacteristics;
import android.hardware.camera2.CameraDevice;
import android.hardware.camera2.CameraManager;
import android.hardware.camera2.CameraMetadata;
import android.hardware.camera2.CaptureRequest;
import android.hardware.camera2.TotalCaptureResult;
import android.hardware.camera2.params.StreamConfigurationMap;
import android.media.Image;
import android.media.ImageReader;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.util.Size;
import android.util.SparseIntArray;
import android.view.Surface;
import android.view.TextureView;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import java.nio.ByteBuffer;
import java.util.Arrays;
public class Camera2Activityextends AppCompatActivity {
private TextureViewtextureView; //预览界面
private ImageViewimageView;
private TextViewcapture;
private TextureView.SurfaceTextureListenersurfaceTextureListener;
private CameraDevice.StateCallbackmStateCallback;//相机开启回调
//摄像头设备，它有一系列参数（预览尺寸、拍照尺寸等），可以通过CameraManager的getCameraCharacteristics()方法获取。
// 它的作用主要是创建CameraCaptureSession和CaptureRequest
private CameraDevicemCameraDevice;
private CameraManagercameraManager;//管理手机上的所有摄像头设备，它的作用主要是获取摄像头列表和打开指定的摄像头
private SurfacemPreviewSurface;//预览Surface
private SurfacemPhotoSurface;//拍照Surface
private ImageReaderimageReader;
private StringmCameraId;//相机id，区分前后置相机
private SizemPreviewSize;//预览尺寸
// private Size captureSize;//成像尺寸
private Bitmapbitmap;
private CameraCaptureSessionmSession;//相机捕获会话，用于处理拍照和预览的工作
private CaptureRequestmCaptureRequest;//捕获请求，定义输出缓冲区以及显示界面（TextureView或SurfaceView）等
private CaptureRequest.BuildermCaptureRequestBuilder;
private CameraCaptureSession.CaptureCallbackmSessionCaptureCallback;//相机捕获会话请求回调
private static final SparseIntArrayORIENTATION =new SparseIntArray();
static {
ORIENTATION.append(Surface.ROTATION_0, 90);
ORIENTATION.append(Surface.ROTATION_90, 0);
ORIENTATION.append(Surface.ROTATION_180, 270);
ORIENTATION.append(Surface.ROTATION_270, 180);
}
/**
* 流程：
* 1.获取CameraManager
* 2.通过CameraManager根据ID获取摄像头参数CameraCharacteristics,获取输出尺寸
* 3.通过CameraManager开启摄像头，并在回调中获取到CameraDevice对象。
* 4.通过CameraDevice对象创建CameraCaptureSession。
* 5.构建CaptureRequest请求,分别有预览/拍照/录像三种模式
* 6.通过CameraCaptureSession发起请求（capture方法只发一次, setRepeatingRequest方法会一直发）。
* 7.在ImageReader的回调中处理拍照结果。
*/
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera2);
findViews();
initValues();
setListeners();
}
private void findViews(){
textureView = findViewById(R.id.textureView);
imageView = findViewById(R.id.imageView);
capture = findViewById(R.id.capture);
}
private void initValues(){
//获取CameraManager
cameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
initSurfaceTextureListener();
}
private void setListeners(){
textureView.setSurfaceTextureListener(surfaceTextureListener);
capture.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
takePhoto();
}
});
}
private void initSurfaceTextureListener(){
surfaceTextureListener =new TextureView.SurfaceTextureListener() {
@Override
public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
openCamera(false);
}
@Override
public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {
}
@Override
public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
return false;
}
@Override
public void onSurfaceTextureUpdated(SurfaceTexture surface) {
}
};
}
private CameraDevice.StateCallbackinitStateCallback(){
if(mStateCallback ==null){
mStateCallback =new CameraDevice.StateCallback() {
@Override
public void onOpened(@NonNull CameraDevice camera) {
mCameraDevice = camera;
openPreview();
}
@Override
public void onDisconnected(@NonNull CameraDevice camera) {
}
@Override
public void onError(@NonNull CameraDevice camera, int error) {
}
};
}
return mStateCallback;
}
private SurfacegetmPreviewSurface(){
if (mPreviewSurface ==null) {
SurfaceTexture mSurfaceTexture =textureView.getSurfaceTexture();
//设置TextureView的缓冲区大小
mSurfaceTexture.setDefaultBufferSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());
//获取Surface显示预览数据
mPreviewSurface =new Surface(mSurfaceTexture);
}
return mPreviewSurface;
}
private SurfacegetmPhotoSurface(){
if (imageReader ==null) {
imageReader = ImageReader.newInstance(mPreviewSize.getWidth(), mPreviewSize.getHeight(), ImageFormat.JPEG, 2);
imageReader.setOnImageAvailableListener(new ImageReader.OnImageAvailableListener() {
@Override
public void onImageAvailable(ImageReader reader) {
getCaptureData(reader);
}
},null);
mPhotoSurface =imageReader.getSurface();
}
return mPhotoSurface;
}
private void closeCamera() {
if (mSession !=null) {
mSession.close();
mSession =null;
}
if (mCameraDevice !=null) {
mCameraDevice.close();
mCameraDevice =null;
}
if (imageReader !=null) {
imageReader.close();
imageReader =null;
mCaptureRequestBuilder =null;
}
}
private void openCamera(boolean isFront){
closeCamera();
if(isFront){
mCameraId = CameraCharacteristics.LENS_FACING_FRONT +"";
}
else {
mCameraId = CameraCharacteristics.LENS_FACING_BACK +"";
}
setCameraData();
try {
if (checkPermission()) {
//打开相机
cameraManager.openCamera(mCameraId, initStateCallback(), null);
}
}catch (CameraAccessException e) {
e.printStackTrace();
}
}
//设置相机参数
private void setCameraData(){
try {
//获取相机的参数
CameraCharacteristics characteristics =cameraManager.getCameraCharacteristics(mCameraId);
//获取摄像头支持的所有输出格式和尺寸
StreamConfigurationMap map = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
Size[] previewSizes = map.getOutputSizes(SurfaceTexture.class);//获取所有预览尺寸
mPreviewSize = previewSizes[0];//获取预览尺寸
//设置预览尺寸
textureView.getSurfaceTexture().setDefaultBufferSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());
}catch (CameraAccessException e) {
Log.getStackTraceString(e);
}
}
//开启预览
private void openPreview(){
try {
mCaptureRequestBuilder =mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
mCaptureRequestBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
mCaptureRequestBuilder.addTarget(getmPreviewSurface()); //设置Surface作为预览数据的显示界面
mCameraDevice.createCaptureSession(Arrays.asList(getmPreviewSurface(), getmPhotoSurface()),
new CameraCaptureSession.StateCallback() {//创建Session，需先完成画面呈现目标（此处为预览和拍照Surface）的初始化
@Override
public void onConfigured(@NonNull CameraCaptureSession session) {
try {
//构建预览请求，并发起请求
Log.e("","[发出预览请求]");
mSession = session;
mCaptureRequest =mCaptureRequestBuilder.build();
session.setRepeatingRequest(mCaptureRequest, getmSessionCaptureCallback(), null);
}catch (CameraAccessException e) {
Log.e("",Log.getStackTraceString(e));
}
}
@Override
public void onConfigureFailed(@NonNull CameraCaptureSession session) {
session.close();
}
}, null);
}catch (CameraAccessException e) {
Log.e("",Log.getStackTraceString(e));
}
}
//获取拍照数据
private void getCaptureData(ImageReader reader){
Image image = reader.acquireLatestImage();
ByteBuffer buffer = image.getPlanes()[0].getBuffer();
byte[] data =new byte[buffer.remaining()];
buffer.get(data);
image.close();
if (bitmap !=null) {
bitmap.recycle();
bitmap =null;
}
bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
data =null;
if (bitmap !=null) {
showImage(bitmap);
}
Runtime.getRuntime().gc();
}
/**
* 预览回调对象
* @return
*/
private CameraCaptureSession.CaptureCallbackgetmSessionCaptureCallback() {
if (mSessionCaptureCallback ==null) {
mSessionCaptureCallback =new CameraCaptureSession.CaptureCallback() {
public void onCaptureCompleted(@NonNull CameraCaptureSession session, @NonNull CaptureRequest request, @NonNull TotalCaptureResult result) {
}
};
}
return mSessionCaptureCallback;
}
//拍照
private void takePhoto() {
try {
mCaptureRequestBuilder =mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
mCaptureRequestBuilder.addTarget(imageReader.getSurface());
mCaptureRequest =mCaptureRequestBuilder.build();
Log.i(this.getClass().getName(), "发出请求");
mSession.capture(mCaptureRequest, getmSessionCaptureCallback(), null);
}catch (CameraAccessException e) {
Log.e("",Log.getStackTraceString(e));
}
}
//检查权限
private boolean checkPermission(){
if(ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED){
return true;
}
else {
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, 0);
return false;
}
}
private void showImage(Bitmap bitmap){
imageView.setImageBitmap(bitmap);
}
@Override
public void onDestroy(){
super.onDestroy();
closeCamera();
}
}
界面布局：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="@color/colorBlank"
tools:context=".Camera2Activity">
android:id="@+id/textureView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1"
/>
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_gravity="center_horizontal"
android:gravity="center"
>
android:id="@+id/imageView"
android:layout_width="50dp"
android:layout_height="50dp"
/>
android:id="@+id/capture"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingTop="5sp"
android:paddingBottom="5sp"
android:paddingRight="20sp"
android:paddingLeft="20sp"
android:layout_marginLeft="30dp"
android:textSize="16sp"
android:textColor="@color/colorBlank"
android:text="拍照"
android:background="@color/colorSelect"
/>
</LinearLayout>
